Hot dogs: Comestible Canids in Preclassic Maya Culture at Cuello, Belize

The contribution of animal protein to the ancient Maya diet, and its means of procurement, can be assessed more accurately on the basis of systematic faunal recovery from recent excavations. We evaluate the presence of dog (Canis familiaris) remains in Preclassic (1200 BC-AD 250) deposits from the Maya site of Cuello, Belize, and conclude that the animals were raised for food and killed at the end of their first year of life. The frequency and distribution of canid bones suggest a significant but not dominant contribution to the meat supply throughout the Preclassic period.     

Nitrogen isotopes and the trophic level of humans in archaeology

Human and domesticate animal bone collagen δ¹⁵N values in prehistory differ generally by 3‰ or more from Neolithic to post- Roman times in Northwest Europe, leading to an assumed dietary animal protein fraction of 60–80% using a standard interpretation of δ¹⁵N values. We examine the assumptions on which this model rests and the limitations of our knowledge in the analysis of δ¹⁵N values in archaeology. We have developed a set of models which, with small changes made in assumptions (on the order of 1‰), can produce substantially lower estimates of the dietary animal protein fraction for given δ¹⁵N values. We consider the implications of various dietary animal protein fractions on agricultural carrying capacities and human population densities in prehistory.     

Assessing the reliability of pRIA for identifying ancient proteins from archaeological contexts

The use of immunological techniques for identifying the origin of proteins and inferring foodstuffs exploited by prehistoric occupations has been conducted for several decades. Cases of experimental laboratory and archaeological studies have shown the potential of these techniques for reliable results. However, very few of these case studies employ archaeological sites that have excellent preservation and high-resolution spatial contexts between identifiable faunal remains, features, and stone tools. We present an assessment of the identification reliability of one immunological technique, protein radioimmunoassay (pRIA), using faunal remains and stone tools from two sites from arctic and subarctic contexts. The results of this research indicate that, even in contexts with excellent preservation, the identifications produced by the pRIA technique are subject to misidentification and cross-reactions due to diagenetic alteration of proteins. We propose a higher minimum reaction value (percent binding of labeled antibody) that mitigates these effects, and renders the pRIA results more reliable for ancient, poorly preserved organic remains.     

Integration of use-wear with protein residue analysis – a study of tool use and function in the south Scandinavian Early Neolithic

This study presents research on how an integration of use-wear analysis with protein residue analysis can produce new results on prehistoric tool use and function. Thirty flint artefacts from an Early Neolithic TRB site in south Sweden were analysed for both use-wear and protein residues. The results show a positive correlation between the two methods. The Early Neolithic tools analysed were primarily used to process fish.     

Towards the application of desorption electrospray ionisation mass spectrometry (DESI-MS) to the analysis of ancient proteins from artefacts

The detection and identification of protein residues from archaeological artefacts has been the subject of considerable controversy over the past two decades, this controversy spurring the application of a range of different analytical methods. Part of the debate surrounds the ability of the methods to uniquely identify original proteins. Another is the apparent contradiction between the ease of extraction in the laboratory of residues that have managed to survive in sediment over millennia; some studies use simple solvents including water, whilst others claim that efficient extraction requires the destruction of the artefact.Desorption electrospray ionisation mass spectrometry (DESI-MS) offers the potential to directly analyse proteins bound to the surface of artefacts. The method permits desorption of analytes under ambient conditions directly from a wide range of surfaces with little or no sample preparation. This has already led to its application in a range of areas, including forensic analysis of trace levels of narcotic drugs. It does not require destruction of the artefact (e.g. by drilling or dissolution) and can work in concert with other methods (for instance it could be used as a screening tool prior to lipid extraction).Here we report the construction of a DESI-MS interface and consider the potential of the method to contribute to the debate surrounding the preservation of proteins on artefacts. The DESI-MS interface was fitted to a conventional ion trap mass spectrometer and tested using peptides and proteins artificially applied to the surface of flint flakes and potsherd samples. A range of intact proteins was analysed; the DESI interface identified test proteins up to a maximum molecular weight of approximately 20 kDa. Peptides generated from these and larger proteins could be detected using DESI-MS following tryptic digestion in situ. The collected data allowed identification of the originating proteins. The potential applications to archaeological science of this new analytical tool are discussed.     

壁画、建筑彩绘文物中几种测定蛋白质方法 的比较和评价

蛋白质常作为胶结材料存在于壁画、建筑彩绘文物中。它的老化变质及其流失会使彩绘颜料产生掉色、脱落,胶结材料的含量与该类文物的病害密切相关。因此,定量测定蛋白质含量对彩绘文物的病害机理和修复保护研究具有重要意义。本研究在总结凯氏定氮法、分光光度法等蛋白质含量测定的一般方法的基础上,重点阐述了彩绘文物颜料层和古建油饰彩画地仗层中蛋白质含量测定的常用方法,如气-质联用法、氨基酸分析法、元素分析法。介绍了这些方法的原理、特点以及应用实例。从分析结果来看,以上方法在彩绘文物颜料层和地仗材料中蛋白质含量测定方面发挥着重要作用。     

应用热裂解气相色谱质谱技术对六种蛋白质类胶结材料的分析与鉴别

利用在线甲基化水解-裂解气相色谱质谱(THM-Py-GC/MS)技术对古代壁画、彩绘等文物中常用的骨胶、皮胶、鱼鳔胶、蛋清、蛋黄和猪血等六种蛋白质类胶结材料进行分析,采用盖蒂保护研究所开发的RAdICAL系统对谱图进行解析,总结了每类材料的特征裂解产物。研究表明,吡咯类化合物,特别是吡咯、二吡咯二酮和哌嗪二酮类化合物可以作为骨胶和皮胶的识别组分,鱼鳔胶的识别组分除了上述吡咯类化合物之外,还包括胆固醇类化合物。吲哚类、血/蛋清标记物、磷酸三甲酯、脯氨酸类化合物是蛋清的识别组分。除了含有蛋清的4种识别成分之外,猪血的识别成分还包括胆固醇类化合物。蛋黄的识别组分是磷酸三甲酯、蛋黄标记物和胆固醇类化合物。最后利用主成分分析法(PCA)对福建省泉州市安海县龙山寺千手观音佛像上脱落的膜状残片的数据和六种蛋白质类胶结材料的数据进行解读,确定了膜状残片的蛋白质类有机材料为动物胶(骨胶或皮胶)和蛋清,证明PCA是一种有效的降维和可视化方法。本研究利用PCA技术对THM-Py-GC/MS数据进行分析解读,且结果可信,为之后该技术的发展提供新的契机。     

The use of an improved pRIA technique in the identification of protein residues

Blood and protein residue identification in archaeological research has been a controversial subject for the last 20 years. This paper reports on the use of an improved protein radioimmunoassay (pRIA) technique in identifying protein residues. Results from the blind testing of the original and improved pRIA techniques in identifying bloodstains on experimental lithic artifacts are described and compared. We argue that the improved pRIA technique is highly sensitive and accurate for identifying protein residues to genus, and thus has excellent applications for archaeological research.     

Studies on amerindian dogs, 1: Carbon isotopes in relation to maize in the diet of domestic dogs from early Peru and Ecuador

Work initiated purely as a dating project in support of a craniometric and morphological investigation of domestic dogs from early Peru has proved to have much wider implications. The stable carbon isotoperatios (¹³C/¹²C) of hair samples from ten dogs show that maize formed a significant part of their diet. Radiocarbon dates for these remains have confirmed that they belong to the period well after the cultivation of maize was first established. Stable carbon isotope measurements can thus be used to test for the presence of maize as a dietary constituent at earlier sites even where there is otherwise only indirect evidence for its cultivation. Collagen from animal or human bone is a suitable alternative to hair for this purpose and the method has been successfully applied to collagen dating to c. 3000 BC from the Valdivia culture site of Real Alto, Ecuador, as well as to a series of early Peruvian dogs.     

The survival of biochemical information in archaeological bone

The paper gives a review of the advantages of genetic information potentially available from surviving molecules (especially proteins) in bone. Survival of such information depends on degradative processes during burial. Conventional protein chemical and immunochemical investigations on various organic components remaining in buried archaeological bone are described. The results provide information on the chemistry of collagen degradation, and indicate that polymorphic macromolecules survive at too low a concentration to be easily detectable.